Process for manufacturing manhole cover

Abstract

The invention relates to a process for manufacturing inspection well covers. The method comprises the following: a step of mixing, which is to match and mix sheet molding compounds accounting for 1 to 99 percent of total weight, scattered molding compounds accounting for 1 to 99 percent of total weight and bulk molding compounds accounting for 1 to 99 percent of total weight; a step of preheating a mold cavity which is to preheat the mold cavity of a hydraulic press to be between 100 and 150 DEG C for 1 to 3 hours; a step of charging which is to put the mixed material into the mold cavity or lay profiles and then the residual mixed material; a step of carrying out compression molding which is to carry out compression molding under the pressure between 1,000 and 10,000 KN at the temperature between 100 and 150 DEG C, maintain pressure and preserve heat for 5 to 60 minutes; and a step of cooling. As the inspection well covers are made from sheet molding compounds and scattered molding compounds or bulk molding compounds through compression molding, the inspection well covers have the advantages of high strength, good anti-fracture toughness and the like. In addition, during manufacture, the time of compression molding and heat preservation is short, so as to save energy. As the inspection well covers have no recycling value, the possibility for stealing the inspection well covers is certainly reduced.

Description

technical field [0001] The invention belongs to the technical field of manhole cover manufacturing in municipal engineering, and in particular relates to a manufacturing process of a manhole cover made of composite materials of SMC and BMC or DMC. Background technique [0002] As we all know, the traditional manhole cover is made of cast iron. Because the iron material has the value of recycling, the manhole cover is often stolen by some criminals, which not only causes the loss of national property, but more seriously, the manhole cover is stolen. The inspection well is not covered, and traffic accidents often occur and cause vehicle damage and casualties. [0003] In order to prevent the manhole cover from being stolen, some technologies of setting anti-theft devices on the structure of the manhole cover occur at present. For example, Chinese Patent Nos. 95241036.2, 96232738.7, 99227151.7 etc. all disclose adding anti-theft components on the manhole cover, so that the man...

AI Technical Summary

Problems solved by technology

Although above-mentioned each patented technical scheme has solved the stolen problem of manhole cover to a certain extent, they all have the following problems, add complicated anti-theft device on the manhole cover of simple structure originally, not only make the structure of manhole cover complicated , increase the manufacturing cost, and after a long time of use, the anti-theft device is easy to rust, which makes it impossible to open the manhole cover normally, thus affecting the normal pipeline dredging and maintenance work

[0004] Others are to improve and innovate on the material of the manhole cover, so that it has no recycling value, such as Chinese Patent No. ZL97202338.0, 97207516.X etc.

Although the above-mentioned patents also reduce the possibility of manhole cover being stolen to a certain extent, there are the following defects: the manhole cover made of plastic has poor wear resistance, aging resistance and chemical corrosion resistance, and its bearing capacity decays quickly , the service life is short, and it cannot meet the requirements of heavy traffic in the city

However, inspection shaft covers made of profiled concrete, glass steel, BMC and other materials are not strong enough and easy to break, causing potential safety hazards on the road surface.

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